Catheter based diagnostic and interventional procedures such as angiograms, balloon angioplasty, stenting, atherectomy, thrombectomy, device placement, etc. are commonly employed to treat patients with vascular obstructions or other abnormalities accessible through the vasculature of the human body. Such interventions are less traumatic to the body than previous surgical interventions and therefore are growing in use.
To gain access to the vasculature, the Seldinger technique is commonly employed. This involves placing a small gauge hollow needle through the skin at about a 30 degree angle to intersect the desired vessel, commonly, but not always, the femoral artery in the groin area. The needle is known to have punctured the vessel wall when blood exits the needle at the proximal end. A guidewire is inserted through the needle into the vessel and the needle is removed. A dilator with a lumen sized to fit the guidewire has a leading tapered end and an outside diameter sized to fit closely in an introducer sheath placed over it. The introducer sheath size is selected (typically 5-8 Fr) to accommodate the catheters anticipated to be used in the procedure. The introducer sheath and tapered dilator are advanced together over the guidewire through the skin and into the vessel. The dilator and guidewire are then removed, since the vascular pathway from outside the body through the sheath and into the vessel has been established. A self sealing stretchable valve at the proximal end of the introducer sheath minimizes blood loss from the introducer sheath during the procedure.
Following the procedure and after all of the catheters and guidewires have been removed from the body, the introducer sheath is removed from the artery. Historically, this has been done by exerting manual pressure on the vessel upstream from the access site to lower blood pressure while the introducer sheath was removed. Once removed, manual pressure is applied directly to the skin above the access puncture for about thirty minutes to inhibit blood loss until the body's natural clotting process sealed the puncture. This technique is generally considered unsatisfactory because it is uncomfortable for the patient and requires a significant amount of nursing staff time.
Sealing the artery by manual compression is rapidly being replaced by medical devices designed to provide a vascular puncture seal in less than five minutes. These devices are intended to be effective and easy to use by medical personnel. The devices range from mechanical suturing devices to collagen plugs, vascular clips, staples, and use of adhesives and sealants. These various approaches have had varying degrees of success and ease of use.
One of the more commonly used devices for closing vessel punctures achieves hemostasis at the vessel puncture site by closing the puncture with an absorbable intra-vessel (e.g., intra-arterial) anchor and an extra-vessel (e.g., extra-arterial) collagen sponge. The anchor and collagen are held together with a self tightening suture loop and slip knot, which, when tightened, sandwiches the puncture hole between the anchor and the collagen sponge. The device is easy to use and the bio-absorbable anchor, collagen, and suture sandwich seals the vessel quickly, is more comfortable for the patient, saves valuable nurse time, and allows early patient ambulation.
Although such collagen devices can be highly effective, a substantial number of punctures in, for example, the femoral artery, may cause the patient to be ineligible to use such a device. Factors that may prevent use of this device include presence of peripheral vascular disease, poor needle stick location (too high or too low), or small vessel size which interferes with anchor placement and prevents proper seating of the anchor against the arterial wall.
In an effort to overcome some of these problems, vascular closure devices have been developed that deposit a plug outside the vessel with no component inside the vessel. Such devices may generally require, however, consistently placing the plug near the arterial wall. Unfortunately, these devices suffer from a number of drawbacks. For example, the pressure exerted on the plug as the heart beats can cause the plug to move away from the hole in the vessel resulting in a hematoma or other complication at the puncture site. Also, the plug may not seal the puncture tract/hole in the blood vessel sufficiently to prevent leakage.
Accordingly, it would be desirable to provide an improved vascular closure device or vascular sealing device that is easy to use, seals quickly and securely, and leaves no component in the blood vessel. A number of embodiments of such improved vascular closure devices are shown and described herein.